In conventional multiple-ratio transmissions, a hydrokinetic torque converter typically is included in the driveline. It is located between the crankshaft of an internal combustion engine and the multiple-ratio gearing that establishes torque flow paths to the vehicle traction wheels. Attempts have been made to eliminate the torque converter from the driveline in order to eliminate the inherent hydrokinetic efficiency losses at the converter. Elimination of the torque converter also reduces the rotary mass of the torque transfer elements at the input side of the multiple-ratio gearing. A transmission of this kind may be seen by referring to copending U.S. patent application Ser. No. 09/353,289, filed Jul. 15, 1999. This application is assigned to the assignee of the present invention.
A gearing arrangement that is capable of being used with the control strategy of the present invention is shown in U.S. Pat. No. 4,938,097. The strategy of the present invention complements the control strategy shown, for example, in U.S. Pat. No. 5,389,046. The complete hydraulic circuit and electronic control strategy for a transmission of the kind shown in the '097 patent is disclosed in the '046 patent. The '097 patent and the '046 patent, as well as application Ser. No. 09/353,289, are incorporated herein by reference.